Work will be continued on studies of the transitions amongst various mesophases and stable phases of the long chain fatty esters of cholesterol. In previous investigations we have studied the behavior of the acetate, the nonanoate, the myristate, and the stearate. We are investigating the hexanoate and propose to study the laurate. It is hoped that ultimately this set of studies will lead to the ability to correlate the structure of these mesophase forming molecules with their transformation behavior. We will continue to use precision dilatometry as the primary investigative tool but we will also carry out ancillary studies of the equilibrium density temperature behavior of these materials in an attempt to elucidate with high precision the temperature behavior of the volume. We will also carry out x-ray diffraction studies of the structures of these systems in various states. We will continue to develop and exploit techniques for studying the energetics of interaction between various substrates and various liquid crystal phases of the cholesteryl esters. These studies have already led to a new method for measuring birefringence of various cholesteric and smectic liquid crystals. The primary ultimate aim of this set of studies is to delineate the transport mechanisms of the most of cholesterol in the blood and to be able to predict on the basis of the structure of the various molecules their ability to transform from one state to another. Secondarily, we hope to provide precise thermodynamic information upon which to base theories about the energetics of transition from one mesophase state to another.